In recent years, high levels of safety performance of vehicles have been required. This trend is shared across countries around the world, where most vehicles are currently standard-equipped with airbags as vehicle safety devices. Firms involved in vehicle development have adopted ongoing safety improvement as a major development guideline. In keeping with this new airbags are continually being developed.
Standards for evaluating vehicle safety differ from country to country, and firms approach product development such that products can meet evaluation standards in multiple countries. In the United States, for instance, which has the largest automobile fleet in the world Federal Motor Vehicle Safety Standards (FMVSS) are issued by the National Highway Traffic Safety Administration (NHTSA). In a Notice of Proposed Rulemaking (NPRM) for FMVSS, a requirement is proposed that aims at “reducing the probability of occupant ejection from a vehicle through a side window using an ejection mitigation system in the event of a side impact or rollover”. The requirement can be met by providing a side curtain airbag as a device intended to reduce ejection from a vehicle, such that the side curtain airbag constitutes the ejection mitigation system.
The side curtain airbag for the vehicle is transversely lengthily installed at the upper end in the vehicle so as to inflate and deploy upon a vehicle collision. The side curtain airbag provides high levels of safety performance upon a rollover as well as a side impact collision of the vehicle.
When an inflator is operated according to an impact signal, the gas generated from the inflator is introduced into the curtain airbag to inflate the curtain airbag, and the inflated curtain air bag is deployed in the vehicle to protect the occupant from a vehicle impact.
In general, the inflator is disposed at the upper rear portion or central portion of the curtain airbag such that gas generated from the inflator flows in the inflatable chamber so as to inflate the inflatable chamber.